Communication method and apparatus

Abstract

A communication method and apparatus are provided, and relate to the field of wireless communication technologies, to resolve a problem in a conventional technology that communication quality during communication between a satellite and a communication apparatus cannot be ensured, and to ensure security of high-accuracy location information of the satellite. In the method, the communication apparatus may perform random access to the satellite based on first location information. The communication apparatus may perform uplink communication with the satellite based on obtained second location information. Accuracy of a location obtained based on the second location information is higher than accuracy of a location obtained based on the first location information. Based on this solution, required accuracy of location information of the satellite is different.

What is claimed is: 
     
         1 . A communication method, comprising:
 obtaining, by a communication apparatus, first location information broadcast by a satellite prior to random access, wherein the satellite is a serving satellite or a target satellite;   after obtaining the first location information, performing, by the communication apparatus, random access based on the first location information;   obtaining, by the communication apparatus, second location information sent by the satellite by using signaling used for the random a based on the first location information, wherein accuracy of a location obtained based on the second location information is higher than accuracy of a location obtained based on the first location information; and   performing, by the communication apparatus, uplink communication based on the second location information.   
     
     
         2 . The method according to  claim 1 , wherein the first location information comprises a basic orbital parameter of the satellite, or the first location information comprises a basic orbital parameter and a perturbation parameter of the satellite. 
     
     
         3 . The method according to  claim 1 , wherein the first location information further comprises motion information of the satellite, and the motion information comprises a motion velocity and a motion direction of the satellite. 
     
     
         4 . The method according to  claim 1 , wherein the second location information is a correction parameter for correcting the first location information. 
     
     
         5 . The method according to  claim 1 , wherein the first location information and the second location information are sent to the communication apparatus at different moments, wherein the second location information is encrypted by using a first key. 
     
     
         6 . The method according to  claim 5 , further comprising:
 obtaining, by the communication apparatus, the first key for decrypting the second location information; and   the obtaining, by the communication apparatus, second location information of the satellite comprises:   decrypting, by the communication apparatus, the second location information of the satellite by using the first key.   
     
     
         7 . The method according to  claim 6 , wherein the first key is pre-stored or sent by the serving satellite. 
     
     
         8 . A communication method, comprising:
 broadcasting, by a serving satellite, first location information of a second satellite to a communication apparatus so that the communication apparatus performs random access based on the first location information, wherein the second satellite is the serving satellite or a target satellite;   sending, by the serving satellite, second location information to the communication apparatus by using signaling used for the random access after the communication apparatus performs random access based on the first location information, wherein accuracy of a location obtained based on the second location information is higher than accuracy of a location obtained based on the first location information; and   performing, by the serving satellite, downlink communication with the communication apparatus based on the second location information.   
     
     
         9 . The method according to  claim 8 , wherein the first location information comprises a basic orbital parameter of the second satellite, or the first location information comprises a basic orbital parameter and a perturbation parameter of the second satellite. 
     
     
         10 . The method according to  claim 8 , wherein the first location information further comprises motion information of the second satellite, and the motion information comprises a motion velocity and a motion direction of the second satellite. 
     
     
         11 . The method according to  claim 8 , wherein the second location information is a correction parameter for correcting the first location information. 
     
     
         12 . The method according to  claim 8 , wherein the first location information and the second location information are sent to the communication apparatus at different moments, wherein the second location information is encrypted by using a first key. 
     
     
         13 . The method according to  claim 12 , further comprising:
 sending, by the serving satellite to the communication apparatus, the first key for decrypting the second location information.   
     
     
         14 . A communication system, comprising a communication apparatus and a serving satellite, wherein the communication apparatus is configured to:
 obtain first location information broadcast by a satellite prior to random access, wherein the satellite is the serving satellite or a target satellite;   after obtaining the first location information, perform random access based on the first location information received from the satellite;   obtain second location information sent by the satellite by using signaling used for the random access performed based on the first location information, wherein accuracy of a location obtained based on the second location information is higher than accuracy of a location obtained based on the first location information; and   perform uplink communication based on the second location information; and   the serving satellite is configured to:   broadcast the first location information of a second satellite to the communication apparatus, wherein the second satellite is the serving satellite or the target satellite;   send the second location information to the communication apparatus after the communication apparatus performs the random access based on the first location information; and   perform downlink communication with the communication apparatus based on the second location information.   
     
     
         15 . The communication system according to  claim 14 , wherein the first location information comprises a basic orbital parameter of the satellite, or the first location information comprises a basic orbital parameter and a perturbation parameter of the satellite. 
     
     
         16 . The communication system according to  claim 14 , wherein the first location information further comprises motion information of the satellite, and the motion information comprises a motion velocity and a motion direction of the satellite. 
     
     
         17 . The communication system according to  claim 14 , wherein the second location information is a correction parameter for correcting the first location information. 
     
     
         18 . The communication system according to  claim 14 , wherein the first location information and the second location information are sent to the communication apparatus at different moments, wherein the second location information is encrypted by using a first key.